checking user defined types

David Eppstein eppstein at ics.uci.edu
Thu Jun 24 08:31:10 CEST 2004


In article <RmuCc.1142728$A6.4637536 at telenews.teleline.es>,
 "Luis Solís" <lsolis at mu.intecsa-inarsa.es> wrote:

> I have defined a class Myclass
> 
> I instanciate the class and I use it in a function, and I could like check
> the argument type in the function, but this code don't works
> 
> func (xMyclass,..):
>     if  type(xMyclass) is type(Myclass): ...
> 
> then I must create a new object of the class and then
> 
> if type(xMyclass) is type(Myclass()):
> 
> this solution has the problem when Myclass has a complex constructor.
> Do you known another solution ?

Why do you think an instance object should have the same type as a class 
object?

You could do
    if type(xMyclass) is Myclass: ...
but that only works for new-style classes and also doesn't match 
instances of subclasses of your class.  Probably what you really want is
    if isinstance(xMyclass, Myclass): ...

-- 
David Eppstein                      http://www.ics.uci.edu/~eppstein/
Univ. of California, Irvine, School of Information & Computer Science



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